MAX1190
Dual 10-Bit, 120Msps, 3.3V, Low-Power ADC
with Internal Reference and Parallel Outputs
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Detailed Description
The MAX1190 uses a nine-stage, fully differential,
pipelined architecture (Figure 1) that allows for high-
speed conversion while minimizing power consump-
tion. Samples taken at the inputs move progressively
through the pipeline stages every half-clock cycle.
Including the delay through the output latch, the total
clock-cycle latency is five clock cycles.
Flash ADCs convert the held input voltages into a digi-
tal code. Internal MDACs convert the digitized results
back into analog voltages, which are then subtracted
from the original held input signals. The resulting error
signals are then multiplied by 2, and the residues are
passed along to the next pipeline stages, where the
process is repeated until the signals have been
processed by all nine stages.
Input Track-and-Hold Circuits
Figure 2 displays a simplified functional diagram of the
input T/H circuits in both track and hold mode. In track
mode, switches S1, S2a, S2b, S4a, S4b, S5a, and S5b
are closed. The fully differential circuits sample the input
signals onto the two capacitors (C2a and C2b) through
switches S4a and S4b. S2a and S2b set the common
mode for the amplifier input, and open simultaneously
with S1, sampling the input waveform. Switches S4a,
S4b, S5a, and S5b are then opened before switches
S3a and S3b connect capacitors C1a and C1b to the
output of the amplifier and switch S4c is closed. The
resulting differential voltages are held on capacitors
C2a and C2b. The amplifiers are used to charge capac-
itors C1a and C1b to the same values originally held on
C2a and C2b.
Pin Description (continued)
PIN NAME FUNCTION
40 D5A Three-State Digital Output, Bit 5, Channel A
41 D6A Three-State Digital Output, Bit 6, Channel A
42 D7A Three-State Digital Output, Bit 7, Channel A
43 D8A Three-State Digital Output, Bit 8, Channel A
44 D9A Three-State Digital Output, Bit 9 (MSB), Channel A
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